Color measurement system

ABSTRACT

A color measurement system includes a hand held color measurement instrument, which may be provided with a wireless interface to a computer. The color measurement system includes a scanning guide for holding the hand held color measurement instrument in proper alignment with a color target. The scanning guide includes a calibration reference to allow convenient calibration of the hand-held color measurement instrument. The hand-held color instrument includes an illumination ring to provide visual feedback to the user. The color of the illumination ring changes in order to display a color similar to that being read by the hand-held color measurement instrument. Color management profiling of the hand held color measurement instrument illumination ring improves the color rendition capability of the illumination ring.

RELATED APPLICATIONS

This patent application claims the benefit of to Provisional PatentApplication No. 60/566,813, filed Apr. 30, 2004, and entitled “COLORMEASUREMENT INSTRUMENT”. This application incorporates by referencepatent application Ser. No. 11/119,867, filed on May 2, 2005, andentitled “Method for Operating a Color Measurement System” and patentapplication Ser. No. 11/119,866, filed on May 2, 2005 and entitled“Color Code for Color Measurement System”.

BACKGROUND OF THE INVENTION

Color management products allow the creation of device characterizationprofiles for various input or output devices, such as printers. Theseprofiles, such as ICC (International Color Consortium) compliantprofiles, allow for proper color handling across many types of devicesin digital workflow of computer images. For example, in order to createa printer profile, the printer creates a sheet of color patches arrangedin a predetermined pattern. A spectrophotometer then scans the colorpatches. The absolute measurements made by the spectrophotometercomprise a set of data that characterizes the producible color gamut ofthe printing device, ink, and media combination. From this data set, aprofile for the device is created. The device profile then may be usedto insure uniform color display.

Recently, hand-held spectrophotometers have been developed for use incolor management. The hand-held spectrophotometers are in many wayseasier and more convenient to use than larger spectrophotometers.However, current hand-held spectrophotometers do have certaindisadvantages. individual color readings. A mechanical linear feedbackmechanism such as a wheel is placed in contact with the color patches.As the spectrophotometer is moved, the wheel measures the speed anddirection of such movement. Because the wheel is contact with the colorpatches, the wheel may distort the color patches, making the measurementby the spectrophotometer inaccurate. Additionally, the wheel, due to useor malfunction, may inaccurately measure the distance, and therebycausing faulty readings of the color patches resulting in re-scanning ora poor quality device profile.

Second, the hand-held spectrophotometer may be allowed to contact thesheet of color patches during the scan. The contact by the hand-heldspectrophotometer may alter the visual appearance as well as theabsolute color where the contact occurs, and thus result in inaccuratereadings and a poor quality device profile. An example of such a deviceis the “EyeOne”, manufactured by Gretag-Macbeth AG

Third, the hand-held spectrophotometer must be tethered to a computer,usually by a serial or USB (Universal Serial Bus) cable. The informationgathered by the spectrophotometer is sent to the computer by way of theUSB cable. Thus, the length of the USB cable restricts the area wherethe spectrophotometer may be used. This is inconvenient, especially ifthe device being measured by the spectrophotometer is not located nearthe computer. Insufficient work surface around computer workstations, toadequately scan over a printed target without cord binding or scaninfluence and interference, also leads to inaccurate readings and a poorquality device profile.

An improved color measurement system that provides for more accuratecolor readings and can be used away from the computer is thus highlydesirable.

SUMMARY OF THE INVENTION

In order to provide a compact, easily useable handheld color measurementinstrument, the color measurement instrument is provided with animproved scanning guide system. To assist in maintaining alignment ofthe detector array with the color patches, the scanning guide isprovided with a plateau that fits within a wide notch located on thebase of the color measurement instrument. As the color measurementinstrument is translated across the scanning guide, theinterrelationship of the wide notch and the plateau maintain thelocation of the detector array in a proper orientation with respect tothe color chart.

Additionally, the plateau includes a number of markings across its top.An optical linear position feedback sensor located in the base of thecolor measurement instrument uses the markings to determine the lateralmovement of the color measurement instrument. Thus, the colormeasurement instrument never comes into contact with the color chart,thereby minimizing the distortions to the color chart.

The scanning guide further includes a calibration reference convenientlyintegrated into the top of the scanning guide. A calibration plateau ofthe same general size as the wide notch in the base of the colormeasurement instrument is provided near the calibration strip. Tocalibrate the color measurement instrument, the wide notch is engagedwith the calibration plateau, thus properly aligning the colormeasurement instrument detector array with the calibration strip,thereby enhancing the calibration of the color measurement instrument.

The scanning guide system may also include a vertical guide. Thevertical guide allows the scanning guide to move accurately up and downon the color chart. The relationship of the color measurement instrumentto the color patch groups is maintained, facilitating an accuratereading of the color patch groups that collectively comprise the testtarget.

The color measurement instrument is also provided with a communicationport for attachment to a computer. The communication port could be anywell-known interface. Optionally, the communication port could be awireless interface.

If provided with a battery, the color measurement instrument couldoperate without a physical connection to a computer, thereby providinggreater freedom and flexibility in using the color measurementinstrument. When a color target is read, the data from the color targetis stored in the color measurement instrument. If the color measurementinstrument has a wireless interface, the color measurement instrumentcould then wirelessly transmit the information to a computer.Alternatively, the color measurement instrument could retain the data inmemory and then download the information to the computer if the colormeasurement instrument was later physically connected to a computer byway of a cable or docking system.

The color measurement instrument could also be provided with anillumination ring. The illumination ring simulates the color currentlybeing read by the color measurement instrument. The illumination ring,which may be composed of one or more multi-colored LED arrays, providesimmediate feedback to a user as to the color patch currently being readby the color measurement instrument. Additional user interfaceinformation could be provided (human or remote camera viewable) by wayof the illumination ring by using unique color and illuminationtechniques.

In order to further improve the capabilities of an un-tethered colormeasurement instrument system, the color target read by the colormeasurement instrument may be provided with a target identificationstrip. The target identification strip encodes information about theentire target such as the patches per color strip, the number of colorstrips on the target, the patch size, the gap size and the software usedto create the target. The target identification strip also includes achecksum to insure data integrity.

Further, the color target could be provided with individual stripidentification. The strip identification includes a color encoded startbit and a color encoded end bit. By providing unique start bits and endbits, the color strip can be accurately decoded regardless of thedirection of the scanning of the strip. Further, indexing informationrelating to the strips which comprise a color target, is embedded andstored in the color measurement device memory. The ability of the colormeasurement device to relate this strip identification index withindividual strips, provides for very easy recovery of errors such as anend user missing or duplicating measurement of particular strips.

These and other objects, advantages and features of the invention willbe more readily understood and appreciated by reference to the detaileddescription of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a handheld color measurement instrument in place on ascanning guide.

FIG. 1A shows the handheld color measurement instrument measuring acalibration reference.

FIG. 1B shows the scanning guide attached to a vertical guide.

FIG. 2 is a side view of the handheld color measurement instrument.

FIG. 3 is a bottom view of the handheld color measurement instrument.

FIG. 4 is perspective view of the end of the handheld color measurementinstrument.

FIG. 5 is a block diagram of the handheld color measurement instrument.

FIG. 6 shows a target identification strip.

FIG. 7 shows a color strip with a strip identification prefix andpostfix.

FIG. 8 is a table showing numeric values associated with colors.

FIG. 9 shows the operation of the handheld color measurement instrument.

FIG. 10 shows the patch recognition process performed by the handheldcolor measurement instrument.

FIG. 11 shows the process for data management for the handheld colormeasurement instrument.

FIG. 12 shows the process for operation of an illumination ring.

FIG. 13 shows a method for creating the color profile for theillumination ring.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a handheld color measurement instrument (CMI) 20 in placeon scanning guide 22, thereby forming a color measurement apparatus.Scanning guide 22 includes port 21. The detector array of CMI 20 ispositioned above scanning guide 22. CMI 20 reads a color chart placedbeneath scanning guide 22, through port 21. Scanning guide 22 includesplateau 24. Plateau 24 is arranged to fit within a wide notch located inthe base of CMI 20. Plateau 24 includes markings 26. CMI 20 readsmarkings 26 in order to gauge linear movement of CMI 20.

When CMI 20 is placed onto plateau 24, side stops 25 of scanning guide22 prohibit motion of CMI 20 outside of the scanning guide.

Scanning guide 22 is also provided with calibration plateau 27 andcalibration reference 29. Calibration reference 29 is protected fromcontamination by a protective cover. Calibration plateau 27 has similardimensions to plateau 24. As shown in FIG. 1A, notch 28 can be placedover calibration plateau 27 in order to maintain the location of thedetector array above calibration reference 29. Calibration plateau 27also has raised feature 23 to precisely locate CMI 20. Thus, everythingnecessary to accurately calibrate CMI 20 is located on the scanningguide, thus reducing the possibility of losing essential parts.

FIG. 1B shows scanning guide 22 attached to vertical guide 31. Mostcolor targets are composed of multiple rows of color patches. The colorpatch has a target color.

By providing vertical guide 31, CMI 20 is maintained in a fixed relationto the color chart, thereby facilitating an accurate reading of thecolor chart. By novel use of the aligning features of CMI 20 to scanningguide 22, coupled with aligning features of scanning guide 22 tovertical guide 31, single handed operation is facilitated in both X andY directions over a grid of color patches. X direction motion ismonitored by optical detector reading markings 26, while Y directionmotion is detected by the reading of encoded information within the row,as will be described with reference to FIG. 6 and FIG. 7.

FIG. 2 is a side view of CMI 20. Notch 28 of CMI 20 is more clearlyshown. Due to the interaction of notch 28 with plateau 24, when CMI 20is moved laterally across scanning guide 22, the patch followed by CMI20 is generally linear. Thus, even though a person may be using CMI 20with one hand, CMI 20 will nevertheless proceed in a straight lineduring the scan.

FIG. 3 is a bottom view of CMI 20. The base of CMI 20 consists of threeareas. Detector array 30 is housed in the forward portion of CMI 20.Linear feedback sensor 32 is positioned within notch 28 near the centerof CMI 20. In order to avoid damage to the target 26, linear feedbacksensor 32 is a non-contact linear feedback sensor.

Linear feedback sensor 32 is surrounded by notch glides 34. Notch glides34 as well as forward glide 36 enable CMI 20 to smoothly transversescanning guide 22. Rear section 38 of CMI 20 is aligned so that CMI 20fits snuggly about plateau 24. Slot 35 accommodates raised feature 23 ofscanning guide 22 to maintain CMI 20 in position during calibrationposition.

FIG. 4 is perspective view of the end of CMI 20. Switch 40 is a toggleswitch to change modes of operation of CMI 20. Communication port 42allows connection of CMI 20 to a computer. Communication port 42 ispreferably a USB (Universal Serial Bus) port, but it could also be anIEEE 1394 FIREWIRE port or any other suitable communication port. Powersupply connector 44 allows the use of a conventional power supply as anoptional power input.

CMI 20 also includes actuator 46. When actuator surface 46 is depressed,CMI 20 is energized. Actuator 46 includes illumination ring 48.

Referring to FIG. 1, when an instrument is to measure patches in astrip, a color target is placed underneath scanning guide 22. Port 21 ispositioned over color bar. CMI 20 is placed over plateau 24, thusautomatically aligning detector array 30 over the color bar. Actuator 46is depressed, and CMI 20 is moved across the color bar, thereby readingthe strip of patches. As CMI 20 is moved across the strip, illuminationring 48 changes color or illumination technique, thereby providingimmediate feedback to the user of CMI 20 that a reading is beingsuccessfully performed. The X-position of CMI 20 is calculated by linearfeedback sensor 32.

By accurately maintaining the location of CMI 20 with reference to thecolor target, the color target is correctly read, allowing an accurateset of patch measurements to be easily and confidently completed.Further, since CMI 20 never contacts the color chart, the color chart isnot distorted, thus maintaining the integrity of successive colorpatches on the color target.

FIG. 5 is a block diagram of CMI 20. CMI 20 includes controller 60.Controller 60 regulates the operation of CMI 20. Controller 60 iscoupled to program memory 62 and data memory 64. Program memory 62contains the instructions executed by controller 60. Controller 60stores the detector output from detector array 66 in data memory 64.

Detector array 66 could be a known spectrometer or any other device of asize suitable for packaging within a handheld instrument. Further, thespectrometer architecture must have sufficient small size, and becapable of very rapid successive measurements to allow for the scanningmotion.

Controller 60 is also coupled to linear position feedback sensor 68.Linear position feedback sensor 68 could be an Omron EE-SYS125reflective photomicrosensor. Linear position feedback sensor 68 readsmarkings 26 in a manner to provide an indication of the distance, rate,and acceleration traversed by CMI 20. The output of linear positionfeedback sensor 68 is “ticks” which indicate a movement between twomarkings 26.

Communication interface 70 provides a means for controller 60 todownload information from data memory 64 to a remote computer or anothermemory. As suggested earlier, communication interface 70 could be aconventional USB port. Alternatively, communication interface 70 couldbe a wireless communication means enabling communication by way of an802.11b, 802.11g, BLUETOOTH protocols, or other advanced wirelessprotocols.

Illumination ring 48 is a light source using multi-colored LED (lightemitting diode) array 72. Each LED generates light of a particularcolor. LED array 72 could be comprised of one or more commonly availableRGB (red-green-blue) LEDs, or it could be comprised of a combination ofred LEDs, a green LEDs and blue LEDs as well additional custom colorLEDs depending on precision of color rendition effect desired.Controller 60 regulates the output of multi-colored LED array 72.

CMI 20 is powered by power supply 74. Power supply 74 could be arechargeable power source such as batteries. If power supply 74 wererechargeable batteries, CMI 20 could be provided with a power managementsystem for recharging the rechargeable batteries. If CMI 20 is providedwith an internal power supply, CMI 20 could operate without a physicalconnection to any computer or other power source.

In order to more effectively use CMI 20 when operating without aphysical connection to a computer, an improved method for ordering colorpatches in the CMI 20 data memory 64 could encode data regarding thecolor patches in the color chart. This allows an untethered CMI 20 tolearn about the entire set of patches a color target contains, beforemeasuring the individual strips of color patches, without benefit ofinformation from an external source such as a computer. The color targetdefinition is contained in the TID strip 80.

FIG. 6 shows a TID (target identification) strip 80. TID strip 80contains color-encoded information about the color target. The colorencoded information is contained within subsets of the strip. Eachsubset contains one or more color patches. TID strip 80 follows astandardized layout. Although there are many ways TID strip 80 could beconfigured, one example uses a minimum patch length of about 6millimeters. One default condition may utilize known start and endspacing or markings so that the CMI 20 to recognize the TID strip 80when scanning from either direction.

The first patch of TID strip 80 is the start bit. Preferably, the patchis printed in cyan. The second through fourth patches define the totalnumber of patches contained in each strip by using a color-encodedvalue. The fifth through eighth color patches contain the total numberof patches for the entire target. The ninth patch is a color-encodedvalue defining a value of deviation in millimeters from the default 6millimeter patch size. The tenth patch defines the deviation inmillimeters from a default gap size.

The eleventh through seventeenth color patches are for user definedfields. These fields could allow proper coordination in printingfacilities where multiple printers are being color management profiled,and coordination for measured color targets could be accommodated withthe proper printer device and unique media type.

A checksum in contained within patches eighteen through twenty-three.Patch twenty-four is a reserved field patch. The TID strip 80 terminateswith a stop bit. The stop bit is magenta.

To further assist CMI 20, each color strip could contain informationconcerning the color strip. FIG. 7 shows an SID (strip identificationcolor strip) 82.

Like TID 80, SID 82 could have several different formats. Onesatisfactory layout requires a minimum patch length of six millimeters.SID 82 begins and ends with a minimum five millimeters of white space.The first patch is a start bit using a format of a one-millimeter CMYoverprint followed with a five millimeter white patch. Patches two,three and four contain strip identification information. The next seriesof patch colors contain the actual target measurement strip. SID 82terminates with a stop bit positioned as the last patch in the strip.The stop bit patch contains a format of three millimeters white followedby a three millimeter CMY overprint.

Due to the presence of the stop and start color patches, SID 82 can beread in either direction. After SID 82 is read, software is used todetermine the correct order of the color patches. Because SID 82 can beread in either direction, the operation of CMI 20 is greatly simplified.

FIG. 8 is a table showing numeric values associated with colors forevaluation of TID 80 and SID 82. Other numeric values and colorcombinations could be used to increase the data density per patch color.

FIG. 9 shows the operation of CMI 20. The scanning starts by theinitialization of a timer. Step 100. Spectral data is read andaccumulated. Step 102. The linear position feedback sensor 68 is checkedto determine if motion was detected. Step 104. If so, then the lampintensity is read. Step 106. The number of ticks, the lamp intensity, atime stamp and the spectral data are stored in data memory 64. Step 108.The process then continues.

On the other hand, if linear position feedback sensor 68 indicates thatno motion has occurred, then the timer is checked for a motion timeout.Step 110. A motion timeout indicates that movement of CMI 20 has notoccurred for a relatively long period of time.

If a motion timeout has not occurred, then spectral data is again readand stored. Step 102. On the other hand, if a motion timeout hasoccurred, then the number of ticks stored is checked. Step 112. If thenumber of ticks indicates that little or no movement of CMI 20 hasoccurred, then the CMI 20 is configured to operate in spot processingmode. Step 114. The spectral data is read and converted into areflectance. Step 116. The data is stored in data memory 64. Step 118.

If the number of ticks stored indicates that movement has occurred, thenscan processing starts. Step 120. If the strip is determined to be a TID(step 122), then the TID is analyzed and stored. Step 124. If the stripis determined not to be a TID, then patch recognition is performed onthe strip and the result is converted into reflectances. Step 126. Thestrip is then stored. Step 128.

FIG. 10 shows the patch recognition process performed by CMI 20. Theprocess starts. Step 200. The edges of the strip are detected. Step 202.The strip is then checked for the existence of narrow black edges. Step204. The absence of narrow black edges is indicative of a TID strip. Ifthere are no black edges, the first patch is checked. Step 206. If thefirst patch is not cyan or magenta, then an error has occurred, and theprocess ends. Step 208.

If, on the other hand, the first patch found is cyan or magenta, thenthe strip is processed as a TID strip. Step 210. The patches areconverted to reflectances. Step 212. The TID is parsed. Step 214. TheTID information is then stored. Step 216.

If black edges were detected, then the strip is processed. Step 218. Thestrip is split into patches (step 220) and the patches are converted toreflectances (step 222). The strip identifier is then parsed. Step 224.The strip is then stored. Step 226.

FIG. 11 shows the process for data management. As indicated previously,communication interface 70 could be a USB connection, a IEEE 1394FIREWIRE connection, or a wireless connection. Further, CMI 20 need notbe continuously in communication with a host computer. For example, ifCMI 20 were provided with a battery as well as a USB connection port,CMI 20 could read a color chart and then download the informationobtained from reading the chart to a computer whenever a communicationlink was established between CMI 20 and the computer. Thus, a methodmust be provided to transfer the data from CMI 20 to the computer. Onesuch method is shown in FIG. 11.

CMI 20 waits for a request from a computer. Step 300. If no request isreceived, CMI 20 continues to wait. If a request is received, the typeof request is parsed.

If the request is for a spot (step 302), then the requested spot data isretrieved. Step 304. The spot data is formatted (step 308) and thentransmitted to the computer. Step 306. If the request is for TIDinformation (step 310), then the TID is retrieved from the database(step 312), formatted (step 314) and then transmitted (step 316). If therequest is fro a strip (step 320), then the strip data is retrieved fromthe memory (step 322), formatted (step 324) and then transmitted (step326).

If the request is for target information (step 330), then one strip isretrieved from memory (step 332), formatted (step 334) and transmitted(step 336). After transmission of the strip, CMI 20 determines whetherall of the strip data for the target has been sent. Step 338. If not,the process repeats. If it has, then the request has processed. Step340.

If the request was a clear data request (step 350), the memory iscleared (step 352). Otherwise, the other requests are processed. Step354.

As indicated previously, CMI 20 is provided with illumination ring 48.Illumination ring 48 can be used to provide information to the user ofCMI 20 regarding the operation of CMI 20. For example, illumination ring48 can provide information regarding the status of an operation as wellas the mode of an operation. Illumination ring 48 would display aparticular color, such as red, if a reading by CMI 20 failed, and adifferent color, such as green, when it succeeded. Illumination ring 48also provides a different color for each mode of operation. A differentcolor would be displayed if CMI 20 were operating in a normal mode or acalibration mode. Further, illumination ring 48 can provide visualfeedback to the user of the color being measured by CMI 20 or indicationof the mode of operation. The CMI 20 can perform multiple patch readingor individual single patch reading functions, and the illumination ring48 may be illuminated with custom user feedback illumination techniques.That is, if CMI 20 is reading a color patch that is red, thenillumination ring 48 becomes red. If CMI 20 is reading a color patchthat is green, then illumination ring 48 becomes green. In this way, auser of CMI 20 is provided visual feedback that CMI 20 is operating.

FIG. 12 shows the process for operation of illumination ring 48 ifillumination ring 48 is comprised of one or more multi-colored LEDs.Illumination ring 48 can operate in either fast mode or accurate mode.Fast mode provides for a more rapid display of colors on illuminationring 48, while accurate mode provides for a more accurate rendering ofcolors on illumination ring 48.

A reading is taken. Step 400. If operating in quick mode (step 402), thereading of channels is scaled to the center wavelengths of themulti-colored LEDs. Step 404. The reflectances are then scaled tomulti-color LED settings. Step 406. The multi-colored LEDs are thenilluminated at the settings. Step 408.

If operating in accurate mode (step 410), all channels are scaled toreflectance values. Step 412. The reflectance values are transformed tomulti-color LED settings based on compensation tables, which could beoptionally calculated from an LED profile. Step 414. The multi-coloredLEDs are then set. Step 408.

The LED profile referred to in step 414 is a color profile for theillumination ring 48. Since illumination ring 48 is a display device, acolor profile will enhance the color display capabilities ofillumination ring 48. FIG. 13 shows a method for creating the colorprofile for illumination ring 48. Since illumination ring 48 iscomprised of multi-colored LEDs, a profile for each LED is created. TheCID 20 is used for making a color management profile for a device suchas a printer. The CID contains a color emitting illumination ring 48which can also benefit from generating a color management profile foreach individual CID 20 for proper illumination ring 48 color renditionin a linearized or calibrated way as well as color profiled for theentire of color gamut produced by the illumination ring, much likemaking a color management profile for each individual host computerdisplay monitor. It is envisioned that other display technology, such asLED backlit graphical displays on a Color Measurement Instrument, couldbenefit from this new technique as integrated into an untethered capableColor Measurement device.

First, the LED profile is cleared. Step 450. Any other LEDs are turnedoff. Step 452. The current LED is set to a predetermined intensity. Step454. The LED is read. Step 456. The reading and setting for the LED isstored in memory. Step 458. If the profile for the current LED is notcomplete (step 460), the LED intensity is stepped. Step 462.

If the profile for the current LED is complete (step 460), then thesystem determines if all of the LEDs have been measured. Step 464. Ifnot, the next LED is checked (step 466), and the process repeats. If allLEDs have been measured, then a LED profile is generated (step 468) andthe LED profile is stored in memory (step 470).

The above description is of the preferred embodiment. Variousalterations and changes can be made without departing from the spiritand broader aspects of the invention as defined in the appended claims,which are to be interpreted in accordance with the principles of patentlaw including the doctrine of equivalents. Any references to claimelements in the singular, for example, using the articles “a,” “an,”“the,” or “said,” is not to be construed as limiting the element to thesingular.

1. An apparatus for measurement of a color target comprising: a scanningguide; and a color measurement instrument movably mounted with respectto the scanning guide, the color measurement instrument having a colordetector and a non-contact feedback mechanism for providing directionalinformation; wherein the scanning guide is structurally independent fromthe color measurement instrument and is sized, shaped, and configured toengage the color measurement instrument so as to maintain the colormeasurement instrument in a measurement plane parallel to the colortarget and spaced a predetermined distance from the color target in afirst direction, and to permit the color measurement instrument totranslate relative to the scanning guide in a second direction; andwherein the scanning guide further includes features for measurement bythe non-contact feedback mechanism, permitting the non-contact feedbackmechanism to provide directional information in the second direction. 2.The apparatus of claim 1 further comprising: alignment means foraligning the color measurement instrument in a third direction.
 3. Theapparatus of claim 1 further comprising a calibration reference locatedon the scanning guide.
 4. The apparatus of claim 3 further comprising aholder to assist in aligning the color detector over the calibrationreference.
 5. The apparatus of claim 1 further comprising a stop locatedon the scanning guide for prohibiting motion of the color measurementinstrument beyond the bounds of the scanning guide.
 6. The apparatus ofclaim 1 where the scanning guide further comprises a scanning guideportal.
 7. The apparatus of claim 1 further comprising a vertical guide.8. The apparatus of claim 1 where the scanning guide has a slot to allowalignment of a color strip with the color detector.
 9. The apparatus ofclaim 1 further comprising means for moving the color instrument. 10.The apparatus of claim 1 further comprising a back for placement behindthe color target.
 11. The apparatus of claim 1, wherein the non-contactfeedback mechanism includes a non-contact feedback sensor positioned tomeasure at least one of the group consisting of a distance traversed bythe color measurement instrument; a rate of the color measurement; andan acceleration of the color measurement instrument.
 12. The apparatusof claim 1, wherein the color measurement instrument is configured toprovide an indication during a measurement of whether the measurement isbeing successfully performed.
 13. The apparatus of claim 12, wherein thecolor measurement instrument comprises a light emitting diode (LED)configured to provide the indication.
 14. The apparatus of claim 13,wherein the color measurement instrument comprises an illumination ringconfigured to provide the indication.
 15. The apparatus of claim 1,wherein the color measurement instrument further includes a housingmounted with respect to the scanning guide, each of the color detectorand the non-contact feedback mechanism being mounted in common withrespect to the housing.
 16. An apparatus for measurement of a colortarget comprising: a scanning guide; and a color measurement instrumentincluding a color detector and a non-contact feedback mechanism forproviding directional information, the color measurement instrumentfurther including a housing movably mounted with respect to the scanningguide and incorporating each of the color detector and the non-contactfeedback mechanism; wherein the scanning guide is structurallyindependent from the color measurement instrument and is sized, shaped,and configured to engage the housing so as to maintain the colormeasurement instrument in a measurement plane parallel to the colortarget and spaced a predetermined distance from the color target in afirst direction, wherein the color measurement instrument is configuredto provide an indication during a measurement of whether the measurementis being successfully performed, and wherein the color measurementinstrument is configured to provide the indication considering an outputfrom a non-contact feedback sensor associated with the non-contactfeedback mechanism; and wherein the scanning guide further includesfeatures for measurement by the non-contact feedback mechanism,permitting the non-contact feedback mechanism to provide directionalinformation in a second direction.
 17. An apparatus for measurement of acolor target comprising: a scanning guide; and a color measurementinstrument mounted with respect to the scanning guide and including acolor detector and a non-contact feedback mechanism for providingdirectional information; wherein the scanning guide is structurallyindependent from the color measurement instrument and is sized, shaped,and configured to engage the color measurement instrument so as tomaintain the color measurement instrument in a measurement plane spaceda predetermined distance from the color target in a first direction, andto permit the color measurement instrument to move relative to thescanning guide in a second direction, where the scanning guide has afirst plateau and the color measurement instrument has a notch forengagement with the first plateau to control movement of the colormeasurement instrument relative to the scanning guide in the seconddirection; and wherein the scanning guide further includes features formeasurement by the non-contact feedback mechanism, permitting thenon-contact feedback mechanism to provide directional information in thesecond direction.
 18. The apparatus of claim 17 where a plurality ofmarkings are located on the first plateau.
 19. The apparatus of claim 18where the non-contact feedback mechanism is located proximal to thenotch.
 20. An apparatus for measurement of color target comprising: ascanning guide; a color measurement instrument mounted with respect tothe scanning guide and including a color detector and a non-contactfeedback mechanism for providing directional information the scanningguide being structurally independent from the color measurementinstrument and sized, shaped, and configured to engage the colormeasurement instrument so as to maintain the color measurementinstrument in a measurement plane parallel to the color target andspaced a predetermined distance from the color target in a firstdirection, and to permit the color measurement instrument to moverelative to the scanning guide in a second direction; a calibrationreference located on the scanning guide; a holder to assist in aligningthe color detector over the calibration reference; and a second plateau,the holder attached to the second plateau; wherein the scanning guidefurther includes features for measurement by the non-contact feedbackmechanism, permitting the non-contact feedback mechanism to providedirectional information in the second direction.
 21. An apparatus formeasurement of a color target comprising: a scanning guide; a colormeasurement instrument mounted with respect to the scanning guide andincluding a color detector and a non-contact feedback mechanism forproviding directional information, the scanning guide being structurallyindependent from the color measurement instrument, and being furthersized, shaped, and configured to engage the color measurement instrumentso as to maintain the color measurement instrument in a measurementplane parallel to the color target and spaced a predetermined distancefrom the color target in a first direction, and to permit the colormeasurement instrument to move relative to the scanning guide in asecond direction; and a vertical guide, wherein the scanning guide isslideably attached to the vertical guide; wherein the scanning guidefurther includes features for measurement by the non-contact feedbackmechanism, permitting the non-contact feedback mechanism to providedirectional information in the second direction.
 22. The apparatus ofclaim 21, wherein the scanning guide defines a first plateau and whereinthe color instrument defines a notch, and where the notch and the firstplateau constrain movement of the color measurement instrument in asecond direction and the scanning guide limits movement of the colormeasurement instrument in a third direction.